Short-chain Oligonucleotides Research Articles

Analysis of conformational parameters in nucleic acid fragments. III. Very short chain oligonucleotides. The effect of base stacking.

Studies have been made of conformational parameters in single crystal structures of very short chain oligonucleotides consisting of strands with lengths in the range 2-3 bases. Using published data extracted from the Cambridge structural database for 20 such structures, a total of 14 base-pairs were found, of which 10 were hetero-pairs and 4 homo-pairs. Subjecting these to analysis to examine hydrogen bond parameters, propeller twist, buckle and C1'-C1' separation revealed an average propeller twist of 11.6 degrees, with no dependence of this parameter on hydrogen bonding details. In addition, an analysis of base stacking showed there to be no correlation between in-plane geometry and degree of inter-plane overlap.

The Specificity of a Nuclease from Chicken Pancreas

Abstract The specificity of a chicken pancreas nuclease free from phosphodiesterase and nucleotidase activity was studied. The enzyme did not hydrolyze 2',3'-cyclic phosphates of guanosine, cytidine, or uridine. It rapidly hydrolyzed polyadenylate and more slowly polyuridylate, producing mainly di- and trinucleotides. Little or no mononucleotides were produced. Studies on hydrolysis of ribonucleic acid and deoxyribonucleic acid suggested that the enzyme is mainly an endonuclease which forms short chain oligonucleotides (di-, tri-, and tetranucleotides) that terminate in 5'-phosphate and 3'-hydroxyl. There is little or no bond specificity. Exhaustive digests of RNA do produce some mononucleotides, but the rate of mononucleotide production is very slow. The properties of this pancreatic enzyme were compared to other nucleases.